Angular Position Encoder Calibration for Eccentricity and Wobble Errors
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Solution Overview
Problem
Existing rotary encoders face challenges in achieving high measurement accuracy due to mechanical tolerance issues, runout errors, and wobble errors, which are exacerbated by complex alignment requirements and assembly costs, especially in small encoders with code tracks of small diameters.
Innovation Solution
An angular position encoder system that includes a first dimensioning body and rotary angle sensor means to generate coarse angle signals, combined with a reference encoder for generating precise reference fine angle signals, allowing for the detection and correction of eccentricity and wobble errors through calculation methods and signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical tolerance limits are maintained between measuring means and measuring body for high measurement accuracy, then measurement precision is improved, but device complexity and assembly effort increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction values for eccentricity errors in a lookup table during the manufacturing phase. These correction values are determined in advance based on measured eccentricity parameters, eliminating the need for complex real-time calculations or precise mechanical alignment during assembly. The system simply retrieves pre-computed correction data based on detected shaft positions, resolving the contradiction between measurement precision and assembly complexity.
2Measurement precision
If distance of sensing elements from axis of rotation is reduced to minimize eccentricity angle error, then measurement precision is improved, but device complexity and assembly precision requirements increase
Solution Approach 1:
The patent replaces the mechanical solution of precisely positioning sensing elements close to the rotation axis with a computational approach. Instead of relying on precise mechanical alignment, the system uses a lookup table containing pre-calculated correction values that compensate for eccentricity errors regardless of the sensing element distance. This substitution of mechanical precision requirements with data-processing-based correction resolves the contradiction between measurement precision and manufacturing precision.
3Measurement precision
If complex alignment of measuring body relative to measuring means is performed to maintain mechanical tolerance limits, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent implements self-service by enabling the system to automatically compensate for alignment errors and eccentricity through the lookup table mechanism. During operation, the system detects the actual shaft position and retrieves corresponding correction values without requiring manual intervention or complex alignment procedures. This self-correcting capability eliminates the need for skilled alignment work during assembly, resolving the contradiction between measurement precision and ease of manufacture.
4Measurement precision
If precise positioning of measuring instruments and measuring devices is performed to reduce angular errors, then measurement precision is improved, but loss of time in assembly increases
Solution Approach 1:
The patent applies preliminary action by pre-computing and storing all necessary correction values in the lookup table during the manufacturing and calibration phase. This preliminary preparation eliminates the need for time-consuming precise positioning and alignment procedures during final assembly. The system achieves high measurement precision by simply retrieving pre-calculated data, thereby resolving the contradiction between measurement precision and assembly time.
Data Source
Figure 1a~1b
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AI summary
The present invention relates to an angular position encoder (1) for detecting the respective angle of rotation of a rotational movement of a shaft (50), which is rigidly connected to an externally mounted first dimensioning body (2), which in a coupling state is rotationally rigidly (8) connected to a self-mounted second dimensioning body (7). The present invention further relates to a calibration device (2000) for generating calibration data for a rotary encoder (3000) that detects the angle of rotation of a shaft (3001), and to an adjustment device (4000) designed for generating and transmitting adjustment data for a rotary encoder.